wasmparser(CM+GC): Assert that we never define new core types inside SubtypeArenas (#2168)

Author: fitzgen

crates/wasmparser/src/validator/component_types.rs

@@ -534,7 +534,7 @@ pub enum ComponentValType {
 
 impl TypeData for ComponentValType {
     type Id = ComponentValueTypeId;
-
+    const IS_CORE_SUB_TYPE: bool = false;
     fn type_info(&self, types: &TypeList) -> TypeInfo {
         match self {
             ComponentValType::Primitive(_) => TypeInfo::new(),
@@ -641,7 +641,7 @@ pub struct ModuleType {
 
 impl TypeData for ModuleType {
     type Id = ComponentCoreModuleTypeId;
-
+    const IS_CORE_SUB_TYPE: bool = false;
     fn type_info(&self, _types: &TypeList) -> TypeInfo {
         self.info
     }
@@ -677,7 +677,7 @@ pub struct InstanceType {
 
 impl TypeData for InstanceType {
     type Id = ComponentCoreInstanceTypeId;
-
+    const IS_CORE_SUB_TYPE: bool = false;
     fn type_info(&self, _types: &TypeList) -> TypeInfo {
         self.info
     }
@@ -817,7 +817,7 @@ pub struct ComponentType {
 
 impl TypeData for ComponentType {
     type Id = ComponentTypeId;
-
+    const IS_CORE_SUB_TYPE: bool = false;
     fn type_info(&self, _types: &TypeList) -> TypeInfo {
         self.info
     }
@@ -875,7 +875,7 @@ pub struct ComponentInstanceType {
 
 impl TypeData for ComponentInstanceType {
     type Id = ComponentInstanceTypeId;
-
+    const IS_CORE_SUB_TYPE: bool = false;
     fn type_info(&self, _types: &TypeList) -> TypeInfo {
         self.info
     }
@@ -894,7 +894,7 @@ pub struct ComponentFuncType {
 
 impl TypeData for ComponentFuncType {
     type Id = ComponentFuncTypeId;
-
+    const IS_CORE_SUB_TYPE: bool = false;
     fn type_info(&self, _types: &TypeList) -> TypeInfo {
         self.info
     }
@@ -1080,7 +1080,7 @@ pub enum ComponentDefinedType {
 
 impl TypeData for ComponentDefinedType {
     type Id = ComponentDefinedTypeId;
-
+    const IS_CORE_SUB_TYPE: bool = false;
     fn type_info(&self, types: &TypeList) -> TypeInfo {
         match self {
             Self::Primitive(_)
@@ -3364,6 +3364,10 @@ impl Remap for SubtypeArena<'_> {
     where
         T: TypeData,
     {
+        assert!(
+            !T::IS_CORE_SUB_TYPE,
+            "cannot push core sub types into `SubtypeArena`s, that would break type canonicalization"
+        );
         let index = T::Id::list(&self.list).len() + T::Id::list(self.types).len();
         let index = u32::try_from(index).unwrap();
         self.list.push(ty);

crates/wasmparser/src/validator/types.rs

@@ -52,6 +52,9 @@ pub trait TypeData: core::fmt::Debug {
     /// The identifier for this type data.
     type Id: TypeIdentifier<Data = Self>;
 
+    /// Is this type a core sub type (or rec group of sub types)?
+    const IS_CORE_SUB_TYPE: bool;
+
     /// Get the info for this type.
     #[doc(hidden)]
     fn type_info(&self, types: &TypeList) -> TypeInfo;
@@ -134,7 +137,7 @@ impl TypeIdentifier for CoreTypeId {
 
 impl TypeData for SubType {
     type Id = CoreTypeId;
-
+    const IS_CORE_SUB_TYPE: bool = true;
     fn type_info(&self, _types: &TypeList) -> TypeInfo {
         // TODO(#1036): calculate actual size for func, array, struct.
         let size = 1 + match &self.composite_type.inner {
@@ -156,7 +159,7 @@ define_type_id!(
 
 impl TypeData for Range<CoreTypeId> {
     type Id = RecGroupId;
-
+    const IS_CORE_SUB_TYPE: bool = true;
     fn type_info(&self, _types: &TypeList) -> TypeInfo {
         let size = self.end.index() - self.start.index();
         TypeInfo::core(u32::try_from(size).unwrap())